CC150 - 11.5

Question:

Given a sorted array of strings which is interspersed with empty strings, write a method to find the location of a given string. 

 1 package POJ;
 2
 3 public class Main {
 4
 5     /**
 6      *
 7      * 11.5 Given a sorted array of strings which is interspersed with empty
 8      * strings, write a method to find the location of a given string.
 9      *
10      */
11     public static void main(String[] args) {
12         Main so = new Main();
13     }
14
15     public int search(String[] strs, String str) {
16         if (strs == null || str == null || str.equals("")) {
17             return -1;
18         }
19         return searchR(strs, str, 0, str.length() - 1);
20     }
21
22     private int searchR(String[] strs, String str, int first, int last) {
23         // TODO Auto-generated method stub
24         if (last < first)
25             return -1;
26         int mid = (first + last) / 2;
27         if (strs[mid].isEmpty()) {
28             int left = mid - 1;
29             int right = mid + 1;
30             while (true) {
31                 if (left < first && right > last)
32                     return -1;
33                 else if (right <= last && !strs[right].isEmpty()) {
34                     mid = right;
35                     break;
36                 } else if (left >= first && !strs[left].isEmpty()) {
37                     mid = left;
38                     break;
39                 }
40                 right++;
41                 left--;
42             }
43         }
44         if (str.equals(strs[mid]))
45             return mid;
46         else if (strs[mid].compareTo(str) < 0)
47             return searchR(strs, str, mid + 1, last);
48         else
49             return searchR(strs, str, first, mid - 1);
50     }
51
52 }